The present invention relates to optical devices, and relates more particularly to a multi-lens optical device for use in an optical scanner which provides different scan area and achieves high resolution.
Optical scanner suppliers commonly provide their scanners with a scanner driving program and an application software program. The scanner driving program of an optical scanner provides default settings on resolution, brightness, contrast, color, gray scale, half tone scale, and preview scan area. Regular optical scanners set the final scan area subject to the preview image in the preview scan area. Because conventional optical scanners commonly have only one single lens, they can only select the maximum optical resolution within the scan area for proceeding the scanning operation. For example, if the charge coupled device (image sensor) has 5340 cells and the scan area is 8.5" (A4), the maximum optical resolution of the image is 600 dpi (dot/inch) or 5100 dot cells when only one single lens is used. If a multi-lens optical device is used, different resolutions can be selected with different lenses, and the scan area will be relatively changed. Through the scanner driving program, the scanner user can control the operation of the lenses of the multi-lens optical device. Because conventional optical scanners use only one single lens for scanning, different optical scanners should be used for different scanning operations. Therefore, when to scan the scan area of a different resolution, an additional optical scanner must be installed.